As Congress explores how to overhaul immigration policy, its own architect of the Capitol is struggling with how to enforce current rules for using the E-Verify system to confirm worker eligibility within the legislative branch.

From April to September of this year, several illegal workers were contracted to complete projects on Capitol grounds, according to the AOC inspector general’s semiannual report to Congress.

The AOC requires all contractors use the non-mandatory Internet-based system known as E-Verify to confirm the legal status of workers applying to work on a given project. Background checks on five individual workers, however, were ultimately not run through the system, and two of these workers never received badges to work on the Capitol campus.

The report found the workers were not brought on through contractors’ intent to deceive or through the AOC’s disregard for the law. Instead, the inspector general attributed the occurrence to “internal control weaknesses” — or, in this case, a communication breakdown.

The illegal workers submitted fraudulent paperwork, the inspector general said, that would have been detected through E-Verify. The requirement to use the system was handed down from the AOC to the prime contractor, who then was supposed to pass that information along to the subcontractors. The first-tier subcontractor got the memo, but the second-tier subcontractor did not.

These semiannual reports to Congress from the AOC inspector general cover a variety of issues that have occurred during a six-month period. Though they are made available to the public, they are not publicized or posted on the office’s website and are only distributed upon request.

It was not so surprising, then, that lawmakers polled on the findings of the report had not known about them before inquiries Tuesday from CQ Roll Call and offered that as a caveat before weighing in on the larger issues at stake.

“We know it’s happening across the country,” said Sen. Marco Rubio, R-Fla., who has expressed interest in championing some form of immigration policy overhaul. “Ultimately, when you have a system that’s not working well, no sector of our economy is immune to it, including government.”

Rep. Zoe Lofgren of California, the ranking Democrat on the House Judiciary Subcommittee on Immigration Policy and Enforcement, opposes making E-Verify mandatory when the immigration system is in need of a bigger fix.

As a member of the House Administration Committee, however, she conceded that Congress should make sure it follows the policies it sets for itself.

“Whatever you think of E-Verify, if it’s the policy we’ve adopted for the Capitol and its contractors, then it ought to be enforced,” she said. “We need to take whatever steps necessary to make sure whatever decisions we make as a Congress are successfully implemented.”

In a separate report to AOC management, the inspector general recommended “improved internal controls and government oversight to reduce the risk of undocumented workers performing work on the Capitol complex.”

On Tuesday, AOC Communications and Congressional Relations Director Mike Culver said in a statement that “the AOC took immediate steps to ensure our contractors use the e-Verify system to validate their employees have proper documentation to work in the United States.”